In recent years, cellular phone terminals or portable music players have functions (such as WEB browsing) equal to that of personal computers, and accordingly it is required to provide, not only ordinary directional keys, but also a pointing device (similar to a mouse of a personal computer) in which the pointer (mark) continuously moves on a display screen in an analog manner.
As such a device, an analog pointing key structure is known, which has:    (i) a rigid body key top;    (ii) a support member, on a surface of which, the rigid body key top is fixedly attached, where an elastic returning part is provided so as to surround the rigid body key top, and the elastic returning part permits the rigid body key top to be displaced along the above surface and can return the displaced rigid body key top to the original position;    (iii) a ring-form magnetic member which is fastened to the support member so as to surround the rigid body key top, and is interposed between the rigid body key top and the elastic returning part; and    (iv) a magnetic sensor that senses a change in the magnetic flux density due to a displacement of the ring-form magnetic member which operates together with the rigid body key top.
For example, Patent Document 1 discloses an analog pointing key structure which has:    (i) a key top;    (ii) a support member, on a front surface (as an operation surface) of which, the key top is fixedly attached, where a pusher for pushing a contact input part of a substrate is provided on a back surface which faces the substrate;    (iii) a magnet fastened to the support member at a side position from the pusher when it is assumed that the pusher is positioned at the center;    (iv) a magnetic sensor that senses a change in the magnetic flux density due to comovement of the magnet which follows a side shift of the key top; and    (v) an elastic flexible part provided between the magnet and the pusher, so as to permit a displacement (in a pushing direction) of the key top caused by the pushing operation using the key top.